If you sliced up the image in Fireworks, then when it is exported to web files
like you have, the HTML page should contain those same slices. The other files
that I didn't cover before, the images (PNG files), which are the slices, and
the CSS is a style document (
http://www.w3schools.com/css/ - Good CSS tutorial
to explain what that file is/does ). The HTML is the main document and the
others should be linked within the HTML document.
If something is not appearing right we will need to see more of what is going
on either with screenshots, the source code from the HTML & CSS file, etc.